Sprinkler heads are attached to down pipes downwardly which extend from horizontal pipes within a ceiling and protrude from a hole formed in a ceiling plate.
Upon installation of the sprinkler heads in the ceiling, the sprinkler heads are fitted with a protective cap having a sharp end and are attached to respective rising pipes connected to a horizontal pipe disposed within the ceiling. The ceiling plate is then brought into an appropriate position for attachment and moved upwardly to urge it against the protective caps. Thus, the ceiling plate is provided with an indicating mark by the sharp end of a respective protective cap. The sprinkler heads protrude from the ceiling plate at thus marked positions after installation of the ceiling plate in the ceiling after removal of the ceiling plate formed with the indicating mark from the ceiling, it is provided with a plurality of holes around the indicating marking by means of a drill. Each hole has a diameter slightly larger than that of the sprinkler head. The sprinkler heads are then inserted into the holes to secure the ceiling plate at a predetermined position to the ceiling (see Japanese Patent Publication No. 58-16906).
When the ceiling plate formed with the holes is attached in the above manner, an annular gap is formed around the sprinkler head protruding from the hole in the ceiling. Such a gap is formed since the hole formed in the ceiling plate has a diameter larger than that of the sprinkler head. There is a disadvantage in which pipings and electric wirings etc., disposed within the ceiling are visible through the gaps. Also, since the the holes are visible, the ceiling plate is not preferable from an aesthetic point of view. The above gaps also permit dust or dirt within the ceiling to fall into a room. In order to conceal the above gaps, a sprinkler head is conventionally fitted with an escutcheon or a sealing plate.
The escutcheon includes a cylindrical portion and a dish-like flange disposed below the cylindrical portion, the cylindrical portion and the flange being integrally formed. The cylindrical portion is fitted around the body of the sprinkler head, so that the flange conceals the gap in the ceiling.
A conventional escutcheon is formed from a soft resin material in view of its low cost. Such a soft resin material also permits easy attachment of the escutcheon to the sprinkler head. The escutcheon is formed to have a plurality of protrusions in the inner surface of the cylindrical portion. The protrusions are engaged with grooves formed in the sprinkler head when the escutcheon is attached to the sprinkler head, so as to avoid dislodgement of the escutcheon from the sprinkler head (refer to Japanese Utility Model Public Disclosure Nos. 55-162636 and 59-114152). Japanese Utility Model Publication No. 58-2359 discloses an escutcheon including a cylindrical portion which is divided into plural portions by means of a plurality of slits. The plural portions resiliently contribute to securement of the escutcheon to the sprinkler head.
The above escutcheon having simple protrusions or slits may be easily attached to the sprinkler head. Sufficient inter-engagement may be obtained between the escutcheon and the sprinkler head, so that the escutcheon is hardly dislodged from the sprinkler head. This is because a conventional escutcheon is formed from a soft synthetic resin such as polyethylene or polypropylene, so that, upon attachment of the escutcheon to the sprinkler head, the protrusions formed in the cylindrical portion of the escutcheon are deformed to enter the respective grooves in the sprinkler head. With an escutcheon having a cylindrical portion formed with a plurality of slits, the cylindrical portion may be easily deformed upon attachment thereof to the sprinkler head and attached to the sprinkler head by means of its own resiliency.
It is noted, however, that a conventional escutcheon formed from a soft synthetic resin may cause an accident when a fire occurs. When an escutcheon formed from a soft synthetic resin, typically having a low heat resisting property, is directly subjected to a flame during a fire, the escutcheon melts prior to supply of water from a sprinkler head and is adhered to a heat sensitive, breakable portion of the sprinkler head thereby impeding proper actuation thereof. The melted escutcheon may also extend downwardly so as to block water from the sprinkler head, so that a proper spray is not obtained.
The inventor has found that the above problem in the prior art escutcheon formed from a soft synthetic resin may be obviated when an escutcheon is formed from a heat resisting material such as metal or heat resisting synthetic resin which does not melt when subject to strong heat. It was found, however, that an attachment mechanism employed in conventional escutcheon formed from a soft synthetic resin material could not be used when the escutcheon is formed from a heat resisting synthetic resin. Since metal or a heat resisting synthetic resin is very hard, protrusions formed in a cylindrical portion of an escutcheon formed from such hard material could not be inter-engaged with the groove in the sprinkler head. Even when an escutcheon of a heat resisting material is divided into a plurality of tongue portions by means of a plurality of slits, such tongue portions having an arcuate cross-section result in an increase in mechanical strength, so that the escutcheon can not be easily deformed so as to be attached to the sprinkler head. If the tongue portions are forcibly deformed, they tend to be broken or deformed. This causes subsequent dislodgement of the escutcheon from the sprinkler.
When multiple slits are formed in the cylindrical portion of the escutcheon formed from a heat resisting material so as to reduce an arcuate extension of each of the tongue portions, it is possible for the tongue portions to be bent easily and to be fitted over the sprinkler head under their own resiliency. It is noted, however, that an escutcheon having tongue portions which are too narrow has insufficient resilient force so that it may be dislodged from the sprinkler head over time.
Accordingly, the present invention is directed to a provision of an escutcheon including a cylindrical portion formed from metal or heat resisting synthetic resin. The cylindrical portion, when formed with a plurality of slits, has an appropriate resiliency for permitting the escutcheon to be fitted around a sprinkler head. The escutcheon may be easily attached to the sprinkler head.